Financial Instruments (Tables)

9 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Schedule of carrying amount and estimated fair values of our exchangeable notes as well as current and long-term debt

The following table presents carrying amounts and estimated fair values of current and long-term debt:

	Carrying amount at December 31, 2016		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt	$	36,870	$	29,457	$	4,391	$	4,758	$	38,606

	Carrying amount at March 31, 2016		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt	$	33,645	$	21,757	$	4,474	$	2,130	$	28,361